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https://www.readbyqxmd.com/read/29156513/production-and-characterization-of-keratinolytic-proteases-by-a-chicken-feather-degrading-thermophilic-strain-thermoactinomyces-sp-yt06
#1
Lin Wang, Yuting Qian, Yun Cao, Ying Huang, Zhizhou Chang, Hongying Huang
Thermoactinomyces sp. strain YT06 was isolated from poultry compost and observed to degrade integral chicken feathers at 60°C completely, resulting in the formation of 3.24 mg/mL of free amino acid from 50 mL of culture containing 10 g/L chicken feathers. Strain YT06 could grow and secret keratinase using feather as the only carbon and nitrogen sources without other supplement, but complementation of 10 g/L sucrose and 4 g/L NaNO₃ increased the production of the keratinolytic enzyme. The maximum protease activities obtained were 110 U/mL and keratinase were 42 U/mL...
November 21, 2017: Journal of Microbiology and Biotechnology
https://www.readbyqxmd.com/read/29156404/cascaded-signal-amplification-via-target-triggered-formation-of-aptazyme-for-sensitive-electrochemical-detection-of-atp
#2
Xia Li, Jianmei Yang, Jiaqing Xie, Bingying Jiang, Ruo Yuan, Yun Xiang
The construction of reliable sensors for adenosine triphosphate (ATP) detection gains increasing interest because of its important roles in various enzymatic activities and biological processes. Based on a cascaded, significant signal amplification approach by the integration of the aptazymes and catalytic hairpin assembly (CHA), we have developed a sensitive electrochemical sensor for the detection of ATP. The target ATP leads to the conformational change of the aptazyme sequences and their association with the hairpin substrates to form active aptazymes, in which the hairpin substrates are cyclically cleaved by the metal ion cofactors in buffer to release the enzymatic sequences that can also bind the hairpin substrates to generate active DNAzymes...
November 17, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/29155906/a-combined-continuous-wave-electron-paramagnetic-resonance-and-dft-calculations-of-copper-doped-cd0-98cu0-02-prz-trz-ia-metal-organic-framework
#3
Anastasia Kultaeva, Timur Biktagirov, Jens Bergmann, Linda Hensel, Harald Krautscheid, Andreas Pöppl
Continuous wave X-band electron paramagnetic resonance (EPR) and density functional theory (DFT) were successfully applied to explore the incorporation and coordination state of the Cu(2+) ions in the [Cd0.98Cu0.02(prz-trz-ia)] porous metal-organic frameworks. EPR measurements on powder samples and single crystals provided the full electron Zeeman g and copper hyperfine A(Cu) interaction tensors including the orientation of their principal axes frames. DFT computations allowed for a detailed interpretation of the experimental results in terms of coordination symmetry and binding properties of the paramagnetic Cu(2+) ions...
November 20, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29155589/the-reaction-mechanism-of-isopentenyl-phosphate-kinase-a-qm-mm-study
#4
James McClory, David J Timson, Warispreet Singh, Jian Zhang, Meilan Huang
Isopentenyl phosphate kinase (IPK) catalyzes the Mg2+-ATP dependent phosphorylation reactions to produce isopentenyl diphosphate, an important precursor in the synthesis of isopentenols. However, the position of the divalent metal ion in the crystal structures of IPK in complex with ATP and its native substrate IP has not been definitively resolved, and as a result ambiguity surrounds the catalytic mechanism of IP, limiting its exploitation as a biofuel and in drug design. Here we report the conformational change caused by substrate binding and the catalytically competent structure in complex with the metal ion Mg2+ using molecular dynamic simulations and density functional theory-based quantum mechanics/molecular mechanics calculations (B97d/AMBER99)...
November 20, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/29155569/redox-behavior-of-a-dinuclear-ruthenium-ii-complex-bearing-an-uncommon-bridging-ligand-insights-from-high-pressure-electrochemistry
#5
Maximilian Dürr, Johannes Klein, Axel Kahnt, Sabine Becker, Ralph Puchta, Biprajit Sarkar, Ivana Ivanović-Burmazović
A dinuclear ruthenium complex bridged by 2,3,5,6-pyrazinetetracarboxylic acid (μ-LH2(2-)) was synthesized and characterized by X-ray crystallography, cyclic voltammetry under ambient and elevated pressures, electron paramagnetic resonance (EPR) and UV/vis-NIR (NIR = near-infrared) spectroelectrochemistry, pulse radiolysis, and computational methods. We probed for the first time in the field of mixed-valency the use of high-pressure electrochemical methods. The investigations were directed toward the influence of the protonation state of the bridging ligand on the electronic communication between the ruthenium ions, since such behavior is interesting in terms of modulating redox chemistry by pH...
November 20, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/29155567/ratiometric-fluorescent-detection-of-pb-2-by-fret-based-phthalocyanine-porphyrin-dyads
#6
Dongli Zhang, Mengliang Zhu, Luyang Zhao, Jinghui Zhang, Kang Wang, Dongdong Qi, Yang Zhou, Yongzhong Bian, Jianzhuang Jiang
Sensitive and selective detection of Pb(2+) is a very worthwhile endeavor in terms of both human health and environmental protection, as the heavy metal is fairly ubiquitous and highly toxic. In this study, we designed phthalocyanine-porphyrin (Pc-Por) heterodyads, namely, H2Pc-α-ZnPor (1) and H2Pc-β-ZnPor (2), by connecting a zinc(II) porphyrin moiety to the nonperipheral (α) or peripheral (β) position of a metal-free phthalocyanine moiety. Upon excitation at the porphyrin Soret region (420 nm), both of the dyads exhibited not only a porphyrin emission (605 nm) but also a phthalocyanine emission (ca...
November 20, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/29155554/zn-v2o5-aqueous-hybrid-ion-battery-with-high-voltage-platform-and-long-cycle-life
#7
Ping Hu, Mengyu Yan, Ting Zhu, Xuanpeng Wang, Xiujuan Wei, Jiantao Li, Liang Zhou, Zhaohuai Li, Lineng Chen, Liqiang Mai
Aqueous zinc-ion batteries attract increasing attentions due to their low cost, high safety, and potential application in stationary energy storage. However, the simultaneous realization of high cycling stability and high energy density remains a major challenge. To tackle the above-mentioned challenge, we develop a novel Zn/V2O5 rechargeable aqueous hybrid-ion battery system by using porous V2O5 as the cathode and metallic zinc as the anode. The V2O5 cathode delivers a high discharge capacity of 238 mAh g-1 at 50 mA g-1...
November 20, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29155402/synthesis-of-silver-nanoparticles-from-a-desmodium-adscendens-extract-and-its-antibacterial-evaluation-on-wound-dressing-material
#8
Jaya R Lakkakula, Derek Tantoh Ndinteh, Sandy F van Vuuren, Denise K Olivier, Rui W M Krause
The one-pot synthesis of silver nanoparticles (AgNPs) using the medium-polar extract of Desmodium adscendens (Sw.) DC. is presented here as an alternative synthesis of metal NPs. Characterisation of the formed NPs showed polydispersed AgNPs ranging from 15 to 100 nm where the concentration of metal ions was found to play a role in the size and shape of the prepared NPs. It could be established that the flavonoids, saponins, and alkaloids present in the extract acted as both reducing and stabilising agents during the formation of the capped metal NPs...
December 2017: IET Nanobiotechnology
https://www.readbyqxmd.com/read/29155397/facile-phyto-mediated-synthesis-of-silver-nanoparticles-using-chinese-winter-jujube-ziziphus-jujuba-mill-cv-dongzao-extract-and-their-antibacterial-catalytic-properties
#9
Chun-Gang Yuan, Can Huo, Bing Gui, Jing-Fu Liu, Yong-Sheng Chen
The aqueous extract of Chinese winter jujube (Ziziphus jujuba Mill. cv. Dongzao) was used as reducing and capping agents for the synthesis of silver nanoparticles (AgNPs) for the first time. The resulting AgNPs were characterised by UV/Visible (UV-Vis) spectroscopy, atomic force microscope, transmission electron microscopy, selected area electron diffraction, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray and Fourier transform infrared spectroscopy (FTIR). The colloidal solution of AgNPs gave a maximum UV-Vis absorbance at 446 nm...
December 2017: IET Nanobiotechnology
https://www.readbyqxmd.com/read/29154531/study-of-graphene-oxide-structural-features-for-catalytic-antibacterial-gas-sensing-and-metals-decontamination-environmental-applications
#10
Shamaila Sajjad, Sajjad Ahmed Khan Leghari, Anum Iqbal
This study represents a comprehensive review about the structural features of graphene oxide (GO) and its significance in environmental applications. Two Dimensional (2D) GO is tremendously focused in advanced carbon based nanomaterial for environmental applications due to its tunable physicochemical characteristics. Herein, we report foundational structural models of GO and explore the chemical bonding of oxygen moieties with graphite basal plane using various characterization tools. Moreover, the impact of these oxygen moieties and morphology of GO for the environmental applications such as removal of metal ions, catalytic, antibacterial and gas sensing abilities has here been critically reviewed for the first time...
November 20, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29154140/mouthpart-deformities-in-chironomidae-diptera-as-bioindicators-of-heavy-metals-pollution-in-shiroro-lake-niger-state-nigeria
#11
Francis O Arimoro, Yohanna I Auta, Oghenekaro N Odume, Unique N Keke, Adamu Z Mohammed
In this study, mouthpart deformities in Chironomid larvae (Diptera) were investigated in relation to sediment contamination in the Shiroro Lake in Nigeria. Metals and chironomids were sampled monthly at three stations (A-C) between August 2013 and January 2014. Across the stations, zinc ranged (3.9-75mg/g), manganese (1.29-1.65mg/g), lead (0.00-0.10mg/g), iron (101-168mg/g) and copper (0.13-0.17mg/g). The metal ions did not differ significantly (P > 0.05) between the sampling stations. However, zinc and iron ions were significantly different between the sampling seasons (P < 0...
November 16, 2017: Ecotoxicology and Environmental Safety
https://www.readbyqxmd.com/read/29154095/simultaneous-molybdate-mo-vi-recovery-and-hazardous-ions-immobilization-via-nanoscale-zerovalent-iron
#12
Dongxu Qian, Yiming Su, Yuxiong Huang, Huaqiang Chu, Xuefei Zhou, Yalei Zhang
Nanoscale zerovalent iron (nZVI) shows great promise in valuable metal recovery from wastewater due to its high removal capacity. However, nZVI-based processes mainly focus on the sequestration step, ignoring the desorption step, which is crucial for recovery. In this study, a novel method for simultaneous Mo(VI) recovery and hazardous metal ions immobilization by nZVI was developed and the reaction mechanism was further investigated. Results shown that removal capacity of nZVI was significantly influenced by surface charge and the number of active adsorption sites...
October 18, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/29154026/inhibitors-of-metallo-%C3%AE-lactamases
#13
REVIEW
Caitlyn M Rotondo, Gerard D Wright
The β-lactams are the most successful class of antibiotic drugs but they are vulnerable to inactivation by a growing cadre of β-lactamases that now number more than a thousand variants. β-Lactamases operate by one of two general chemical mechanisms either catalyzing β-lactam ring hydrolysis via a covalent enzyme intermediate through the aegis of an active site serine residue or through a noncovalent Zn-dependent mechanism. The Ser-β-lactamases are currently dominant in the clinic and consequently, there has been great effort to identify inhibitors and to co-formulate these with β-lactam antibiotics...
November 15, 2017: Current Opinion in Microbiology
https://www.readbyqxmd.com/read/29153915/in-situ-immobilization-of-layered-double-hydroxides-as-stationary-phase-for-capillary-electrochromatography
#14
Xinhong Yu, Wei Zhou, Zilin Chen
Layered double hydroxides (LDHs) have gained much attention in absorption and extraction fields due to their special structure and properties like high porosity, large surface area and excellent anion exchange capacity. However, LDHs are rarely used in capillary electrochromatography (CEC) by date due to the lack of appropriate immobilization method. In this work, by utilizing the unique coordination bonding between metal ions on LDHs and catechol groups on polydopamine layer, a polydopamine modification method was developed for in situ immobilization of LDHs on the inner surface of fused silica capillary...
November 12, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/29153855/changes-in-element-availability-induced-by-sterilization-in-heavy-metal-contaminated-substrates-a-comprehensive-study
#15
Thomas Krauße, Eileen Schütze, René Phieler, David Fürst, Dirk Merten, Georg Büchel, Erika Kothe
Microbiome analyses of soils and microcosm experiments depend on conditions that include sterilization in order to perform experimental manipulation of microbial communities. Still, they should represent conditions close to nature. When using metal contaminated soils, sterilization methods might alter metal availability. Here, four typical metal contaminated substrates were analyzed, representing different contamination histories and soil types. They included two very poor substrates, as they are often found at metal contaminated sites...
November 10, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/29153721/preparation-of-ruthenium-iii-ion-imprinted-beads-based-on-2-pyridylthiourea-modified-chitosan
#16
M Monier, D A Abdel-Latif, Ibrahim Youssef
Ru(III) ion-imprinted bio-adsorbent based on 2-pyridylthiourea modified chitosan (Ru-PTCS) had been manufactured, investigated and employed for selective extraction of Ru(III) ions from aqueous medium containing interfering metal ions that maybe coexist and compete with Ru(III) ions. Elemental analysis, FTIR and NMR techniques were performed to characterize the chemical structure of the synthesized polymeric materials. The optimum extraction conditions, selectivity and regeneration efficiency were evaluated via batch experiments...
November 10, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/29153714/polyphosphonate-ligands-from-synthesis-to-design-of-hybrid-pegylated-nanoparticles-toward-phototherapy-studies
#17
Maelle Monteil, Hanane Moustaoui, Gennaro Picardi, Fatima Aouidat, Nadia Djaker, Marc Lamy de La Chapelle, Marc Lecouvey, Jolanda Spadavecchia
The use of phosphonate ligands to modify the nanoparticle (NPs) surface has attracted a strong interest in the last years for the design of highly functional hybrid materials. Here, we applied a methodology to synthesize bisphosphonates having functionalized PEG side chains with a specific length in order to design a novel class of hybrid nanomaterials composed by tetraphosphonate-complex-gold COOH-terminated PEG-coated NPs (Bis-PO-PEG-AuNPs). The synthetic approach consist in three steps: (1) Complexation between new phosphonate ligands (Bis PO) and tetrachloroauric acid (HAuCl4) to form gold clusters; (2) adsorption of COOH-terminated PEG molecules (PEG) onto Bis PO-Au complex; (3) reduction of metal ions in that vicinity, growth of gold particles and colloidal stabilization...
November 2, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/29152626/specific-recognition-of-cr-3-under-physiological-conditions-by-allyl-substituted-appendage-rhodamine-and-its-cell-imaging-studies
#18
Anup Kumar Bhanja, Snehasis Mishra, Kaushik Naskar, Suvendu Maity, Krishna Das Saha, Chittaranjan Sinha
An allyloxynitrophenylimio-propylhydroxyl appended rhodamine (RD-3) specifically recognises Cr(3+) in aqueous buffer medium at pH 7.4. The visible light excitable reagent (λex 505 nm) on selective binding to Cr(3+) exhibited a strong fluorescence turn-on response with powerful emission at 557 nm and the tail of this luminescence band is extended to ∼650 nm. Interference studies confirm that other metal ions (27 ions) do not hamper the detection process of Cr(3+). The sensing mechanism is studied by absorption, fluorescence, Job's plot, and (1)H NMR titration studies...
November 20, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29152332/crystal-structure-of-poly-di-aqua-bis-%C3%AE-5-benzene-1-3-di-carboxyl-ato-n-n-di-methyl-formamide-cadmium-ii-disodium-i
#19
Matimon Sangsawang, Kittipong Chainok, Nanthawat Wannarit
The title compound, [CdNa2(C8H4O4)2(C3H7NO)(H2O)2] n or [CdNa2(1,3-bdc)2(DMF)(H2O)2] n , is a new Cd(II)-Na(I) heterobimetallic coordination polymer. The asymmetric unit consists of one Cd(II) atom, two Na(I) atoms, two 1,3-bdc ligands, two coordinated water mol-ecules and one coordinated DMF mol-ecule. The Cd(II) atom exhibits a seven-coordinate geometry, while the Na(I) atoms can be considered to be penta-coordinate. The metal ions and their symmetry-related equivalents are connected via chelating-bridging carboxyl-ate groups of the 1,3-bdc ligands to generate a three-dimensional framework...
November 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
https://www.readbyqxmd.com/read/29150802/ion-imprinted-electrospun-nanofibers-of-chitosan-1-butyl-3-methylimidazolium-tetrafluoroborate-for-the-dynamic-expulsion-of-thorium-iv-ions-from-mimicked-effluents
#20
Prakash Macchindra Gore, Latika Khurana, Suhail Siddique, Anjana Panicker, Balasubramanian Kandasubramanian
The present study explores the innocuous, biocompatible, and extremely competent molecularly imprinted chitosan/RTIL electrospun nanofibers having average diameter of 30 nm for the expulsion of thorium (IV) ions from the mimicked effluent waste. The extended Flory-Huggins theory and three-dimensional molecular modeling have been effectively premeditated via Materials Studio software for enumerating the inter-miscibility and compatibility (Chi parameter (χ) = 1.019, mixing energy (Emix) = 0.603 kcal/mol) of the chitosan/RTIL (1-butyl-3-methylimidazolium tetrafluoroborate)...
November 17, 2017: Environmental Science and Pollution Research International
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